Power converter circuit and solar power system having same

Abstract

A power converter circuit includes: a first transistor being connected with a positive node and a negative node of a photovoltaic panel; a second transistor being connected with the first transistor and the negative node of the photovoltaic panel; a first controller circuit being configured to measure the voltage at a reference node and adjust the gate voltage of the first and second transistors respectively; a third transistor being connected with the reference node and an output node; and a second controller circuit being configured to control the gate voltage of the third transistor. The reference node is connected to the second transistor through a LC network. The first controller circuit is configured to turn off the first and second transistors when the voltage at the reference node exceeds a threshold. The second controller circuit is configured to prevent current from being fed back through the LC network.

What is claimed is: 
     
         1 . A power converter circuit for charging a battery, the power converter circuit comprising:
 a first transistor being connected with a positive node and a negative node of a photovoltaic panel;   a second transistor being connected with the first transistor and the negative node of the photovoltaic panel;   a first controller circuit being configured to measure the voltage at a reference node and adjust the gate voltage of the first and second transistors respectively;   a third transistor being connected with the reference node and an output node; and   a second controller circuit being configured to control the gate voltage of the third transistor;   wherein:   the reference node is connected to the second transistor through a LC network;   the first controller circuit is configured to turn off the first and second transistors when the voltage at the reference node exceeds a threshold; and   the second controller circuit is configured to prevent current from being fed back through the LC network.   
     
     
         2 . The power converter circuit of  claim 1 , wherein the first, second and third transistors are MOSFETS. 
     
     
         3 . The power converter circuit of  claim 1 , wherein the first controller circuit is configured to generate out of phase PWM signals to control the gate voltage of the first and second transistors respectively. 
     
     
         4 . The power converter circuit of  claim 1 , wherein the threshold is about 1 to 2 volts above the fully charged voltage of the battery. 
     
     
         5 . The power converter circuit of  claim 1 , wherein the first controller circuit is configured to adjust the gate voltage of the first and second transistors respectively so that a preset voltage between the positive and negative nodes of the photovoltaic panel is maintained. 
     
     
         6 . The power converter circuit of  claim 1 , wherein the first controller circuit is configured to turn off the gate voltage of the first and second transistors for a predetermined period within every predetermined interval. 
     
     
         7 . The power converter circuit of  claim 6 , wherein during the predetermined period, the open circuit voltage of the photovoltaic panel is measured repeatedly at a predetermined frequency, and the first controller circuit is configured to turn on the gate voltage of the first and second transistors when the difference between two consecutive measurements is less than a predetermined amount. 
     
     
         8 . A solar power system comprising:
 a plurality of photovoltaic panels, each photovoltaic panel comprising a charging node configured to provide a voltage limited current output;   a plurality of batteries, each battery comprising a sensing node configured to preventing the battery from being overcharged or the system from being overloaded;   a plurality of LED luminaires, each LED luminaire comprising a LED driving and control node configured to control the brightness and on/off status of the LED luminaire; and   a master controller being connected with the photovoltaic panels, the batteries and the LED luminaires through a bus, and configured to coordinate the operations thereof; wherein   the charging node comprising a power converter circuit for charging a battery, the power converter circuit comprising:
 a first transistor being connected with a positive node and a negative node of a photovoltaic panel; 
 a second transistor being connected with the first transistor and the negative node of the photovoltaic panel; 
 a first controller circuit being configured to measure the voltage at a reference node and adjust the gate voltage of the first and second transistors respectively; 
 a third transistor being connected with the reference node and an output node; and 
 a second controller circuit being configured to control the gate voltage of the third transistor. 
   
     
     
         9 . The solar power system of  claim 8 , wherein the reference node is connected to the second transistor through a LC network; the first controller circuit is configured to turn off the first and second transistors when the voltage at the reference node exceeds a threshold; and the second controller circuit is configured to prevent current from being fed back through the LC network. 
     
     
         10 . The solar power system of  claim 8 , wherein the master controller comprises a wireless link configured to enable remote system monitoring and control. 
     
     
         11 . The solar power system of  claim 8 , wherein the bus is a two wire power bus or a four wire power and data bus. 
     
     
         12 . The solar power system of  claim 8 , wherein the master controller is configured to turn off all the charging nodes when all the batteries are fully charged. 
     
     
         13 . The solar power system of  claim 8 , wherein the master controller is configured to collect data from each charging node to record how much power has been produced on a day to day basis. 
     
     
         14 . The solar power system of  claim 8 , wherein the sensing node of each battery is configured to allow the battery to be disconnected from the bus when the battery is fully charged. 
     
     
         15 . The solar power system of  claim 8 , wherein the master controller is configured to instruct a battery to be disconnected from the bus. 
     
     
         16 . The solar power system of  claim 8 , wherein through the LED driving and control node, each luminaire is configured to send data indicating the performance of the luminaire back to the master controller. 
     
     
         17 . A solar power system comprising:
 at least a photovoltaic panel, the photovoltaic panel comprising a charging node configured to provide a current output;   at least a battery, the battery comprising a sensing node configured to preventing the battery from being overcharged or the system from being overloaded;   at least an LED luminaire, the LED luminaire comprising a LED driving and control node configured to control the LED luminaire; and   a master controller being connected with the photovoltaic panel, the battery and the LED luminaire through a bus, and configured to coordinate the operations thereof; wherein   the charging node comprising a power converter circuit for charging a battery, the power converter circuit comprising:   a first transistor being connected with a positive node and a negative node of a photovoltaic panel;   a second transistor being connected with the first transistor and the negative node of the photovoltaic panel; and   a first controller circuit being configured to measure the voltage at a reference node and adjust the gate voltage of the first and second transistors respectively;   the reference node being connected to the second transistor through a LC network;   the first controller circuit being configured to turn off the first and second transistors when the voltage at the reference node exceeds a threshold.   
     
     
         18 . The solar power system of  claim 17 , wherein the threshold is about 1 to 2 volts above the fully charged voltage of the battery. 
     
     
         19 . The solar power system of  claim 17 , wherein the first controller circuit is configured to turn off the gate voltage of the first and second transistors for a predetermined period within every predetermined interval. 
     
     
         20 . The power converter circuit of  claim 19 , wherein during the predetermined period, the open circuit voltage of the photovoltaic panel is measured repeatedly at a predetermined frequency, and the first controller circuit is configured to turn on the gate voltage of the first and second transistors when the difference between two consecutive measurements is less than a predetermined amount.